Chevrolet Chevelle 1970 – SS 396 Convertible

Every 1970 Chevelle SS 396 badge tells a small lie, and the parenthetical in this convertible’s own description gives it away. The 396 that year was really a 402, bored out for reasons that had nothing to do with power, and Chevrolet kept the old emblem anyway. This 350-horsepower drop-top adds bucket seats, tilt wheel, air conditioning, and a power top to the story. Read on to find out why the badge and the engine stopped matching.

Chevrolet told a small lie on every 1970 SS 396 badge it stamped, and the parenthetical in this car’s own description gives it away. That ‘(402)’ sitting quietly next to the ‘396’ is not a typo. It is an admission that the engine badge and the engine itself stopped matching that year, and almost nobody who bought one ever noticed or cared. The reason behind that mismatch says a lot about how Detroit navigated regulations in 1970, and why Chevrolet decided the SS 396 name was worth keeping even after the engine underneath it had quietly changed. And on a power-top convertible with air conditioning, how much does the badge really matter?

Why ‘396’ Stopped Meaning 396

For 1970, Chevrolet bored the venerable 396 big-block out by .030 inches, bringing actual displacement to 402 cubic inches, technically a different engine than the one that had worn the 396 badge since 1965. Rather than rebrand the whole lineup and lose the marketing equity built up around SS 396, Chevrolet simply kept the emblems as they were and let the badge lag behind the specs. Nobody has ever definitively nailed down the exact reason for the bore job, but the leading theory ties back to the way regulations of the era treated engines over 400 cubic inches, and boring the 396 out to 402 may have been the path of least resistance.

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Same Badge, Same Performance

Here is the part that matters most if you are actually driving one: the extra six cubic inches changed nothing on the spec sheet. The 350-horsepower L34’s rating carried over unchanged from 1969 to 1970, so a 350-horsepower ‘396’ in a 1970 Chevelle performs identically to its 1969 counterpart. The displacement bump was purely a badge-and-bore footnote, not a performance upgrade. Combined with the SS appearance package, the sport suspension, and this particular car’s drop-top body style, that makes this Chevelle a genuine period-correct SS convertible wearing a slightly misleading engine badge for reasons that had nothing to do with power.

Four Ways to Order a Big Block in 1970

The 1970 Chevelle SS could be had with four big-block engines. The 396-badged 402 came as the 350-horsepower L34, as in this car, or as the solid-lifter L78 rated at 375 horsepower. Above those sat the new 454 in two forms: the LS5 rated at 360 horsepower and the legendary LS6 rated at 450, the highest factory rating of the muscle car era. The L34 was the volume choice, the engine most SS buyers actually drove home, and it delivered strong, tractable big-block torque without the temperament of the solid-lifter engines. It is the sensible heart of an SS that was also ordered with air conditioning.

The 454 Shadow Over the SS 396

The LS6 454 gets most of the attention when 1970 Chevelles come up, and understandably so, but it has also cast a long shadow over the SS 396 cars that made up the bulk of production. A 350-horsepower 402 in a convertible is a far more usable car than a 450-horsepower LS6, and it was priced and equipped for buyers who wanted to drive it every day. In the current market, SS 396 cars offer much of the look and feel of the 454 cars at a fraction of the price, which is why knowledgeable buyers often seek them out rather than chasing the halo engine.

What the SS Package Included

Ordering an SS on a 1970 Chevelle meant checking the Z25 option, which bundled the 402 engine with the F41 sport suspension, power front disc brakes, 15×7 wheels, a blacked-out grille, a domed hood, and the SS badging and trim that make up the appearance package this car’s description mentions. It was a genuine performance package rather than a sticker set, and the sport suspension in particular transformed how a Chevelle handled compared with the base car. The convertible body style added weight, but the suspension and brakes were the same, which makes an SS 396 drop-top a surprisingly composed car on a winding road.

Cowl Induction and the Stripes

The visual signature of the 1970 SS is the optional cowl induction hood, with its rear-facing flap that opened under hard throttle, and the wide hood and deck stripes that so often accompanied it. Neither was required to make an SS, and plenty of cars left the factory with the standard domed hood and no stripes, as this car’s description suggests. That variety is part of what makes the 1970 Chevelle so interesting to collectors: two SS 396 convertibles can look strikingly different depending on how the original buyer filled out the order form, and neither is more correct than the other.

Comfort Options on a Muscle Car

This car was ordered with bucket seats, a tilt steering wheel, air conditioning, and a power convertible top, which tells you something about who bought it. It was not a bare-bones drag car. It was a big-block convertible meant to be enjoyed on the road, with the top down and the air on when the weather demanded it. Factory air conditioning on a big-block Chevelle was a relatively uncommon combination, since many performance buyers skipped it to save money and weight, and it makes this car more desirable to buyers who intend to drive it in the summer rather than store it.

The Convertible Body Style

Convertibles were always the smallest slice of Chevelle production, and SS convertibles smaller still. The 1970 body, with its crisp new sheet metal and aggressive stance, may be the best-looking Chevelle ever built, and the convertible version shows off the lines without the roof interrupting them. Because so many were used hard, rusted, or converted into clones of rarer cars, genuine SS 396 convertibles from 1970 are far scarcer than the model’s overall popularity suggests. A correct example with its original drivetrain and its factory options intact is a rarer find than most people realize.

1970 Was the Peak, and Everyone Knew It

The 1970 model year was the high-water mark for the Chevelle SS and for Detroit muscle in general. Compression ratios dropped across the industry for 1971 to accommodate lower-octane fuel, and the switch to net horsepower ratings in 1972 made the numbers look smaller still. The SS 396 badge itself disappeared after 1970, with the 402 sold simply as a 400 in later cars. That makes 1970 the last year the SS 396 name meant what buyers had understood it to mean since 1965, even if the engine underneath had already grown six cubic inches.

What a Correct SS Convertible Needs Today

The VIN on a 1970 Chevelle does not identify the car as an SS, which is why documentation matters so much. A build sheet, a Protect-O-Plate, or original dealer paperwork is what separates a real SS 396 from a well-built tribute, and on a convertible with air conditioning and a power top, that paperwork should also reflect those options. Buyers should look for the correct engine suffix code, the SS-specific trim and brake components, and evidence that the convertible frame is original. A documented car like this one is worth the extra scrutiny, because the difference in value is substantial.

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